Light emitting device having first and second wavelength converter parts

ABSTRACT

The light emitting device includes a light emitting element, a wavelength converter, and a light guider. The light emitting element has an element upper surface, an element lower surface, and an element side surface. The wavelength converter has a converter lower surface. The wavelength is provided to be connected to the light emitting element. The converter lower surface has an exposed region that does not face the element upper surface. The light guider guides light from the light emitting element to the wavelength converter. The light guider covers the element side surface and the exposed region. The wavelength converter includes first and second wavelength converter parts. The first wavelength converter part faces the element upper surface and has a first thickness. The second wavelength converter part does not face the element upper surface and has a second thickness thinner than the first thickness.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U. S. C. §119 toJapanese Patent Application No. 2014-202194, filed Sep. 30, 2014. Thecontents of this application are incorporated herein by reference intheir entirety.

BACKGROUND

Technical Field

The present disclosure relates to a light emitting device and a methodof manufacturing a light emitting device.

Discussion of the Background

Currently, a semiconductor light emitting device which subjects light ofa light emitting element to wavelength conversion with a phosphor andemits white light by the light from the light emitting element and lightfrom the phosphor is used as a light source of an illumination devicesuch as general lighting, street light, or a head lamp. Of thesedescribed above, for example, for the street light and the head lamp, alight emitting device with high front luminance is required, and variouslight emitting devices have been conventionally suggested.

For example, Japanese Unexamined Patent Application Publication No.2009-218274 suggests a light emitting device including a wavelengthconversion layer and a reflective member for the purpose of ensuringhigh front luminance. The wavelength conversion layer is disposed on theupper portion of the light emitting element, converts the wavelength oflight from a light-emitting element, and is formed of a lighttransmissive member containing a phosphor. The reflective member isdisposed adjacently to a side surface of this wavelength conversionlayer and a side surface of the light emitting element.

Moreover, for the purpose of improving phosphor concentration, JapaneseUnexamined Patent Application Publication No. 2014-120722 suggests alight emitting device including a wavelength conversion member disposedon an upper surface of a light emitting element with a bonding layer inbetween, a light transmissive member disposed on an upper surface of thewavelength conversion member integrally therewith, and a lightreflective member disposed along side surfaces of the light emittingelement, the wavelength conversion member, and the light transmissivemember.

For the purpose of reducing color unevenness on a light emittingsurface, Japanese Unexamined Patent Application Publication No.2012-156180 suggests a light emitting device including aphosphor-containing resin layer disposed on a light emitting element,and a plate-like optical layer loaded on the phosphor-containing resinlayer, wherein the phosphor concentration of the phosphor-containingresin layer is different between a surrounding region of the lightemitting element and a region immediately thereabove.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, a light emittingdevice includes a light emitting element, a wavelength converter, alight transmissive member, a and a light guider. The light emittingelement has an element upper surface, an element lower surface, and anelement side surface. The element lower surface is opposite to theelement upper surface in a thickness direction of the light emittingelement. The element side surface is between the element upper surfaceand the element lower surface. The wavelength converter has a converterlower surface. The wavelength is provided to be connected to the lightemitting element such that the converter lower surface faces the elementupper surface. The converter lower surface has an exposed region thatdoes not face the element upper surface viewed along the thicknessdirection. The light guider guides light from the light emitting elementto the wavelength converter. The light guider covers the element sidesurface and the exposed region. The wavelength converter includes afirst wavelength converter part and a second wavelength converter part.The first wavelength converter part faces the element upper surfaceviewed along the thickness direction and has a first thickness in thethickness direction. The second wavelength converter part does not facethe element upper surface viewed along the thickness direction and has asecond thickness in the thickness direction. The second thickness isthinner than the first thickness.

According to a second aspect of the present invention, a light emittingdevice includes a light emitting element, a wavelength converter, alight transmissive member, a light guider, and a light transmittinglayer. The light emitting element has an element upper surface, anelement lower surface, and an element side surface. The element lowersurface is opposite to the element upper surface in a thicknessdirection of the light emitting element. The element side surface isbetween the element upper surface and the element lower surface. Thewavelength converter has a converter lower surface. The wavelength isprovided to be connected to the light emitting element such that theconverter lower surface faces the element upper surface. The converterlower surface has an exposed region that does not face the element uppersurface viewed along the thickness direction. The light guider guideslight from the light emitting element to the wavelength converter. Thelight guider covers the element side surface and the exposed region. Thewavelength converter has a converter upper surface opposite to theconverter lower surface in the thickness direction. The lighttransmitting layer has a layer lower surface facing the converter uppersurface. The converter upper surface is smaller than the layer lowersurface.

According to a third aspect of the present invention, a method ofmanufacturing a light emitting device, the method includes providing alight emitting element, providing a wavelength converter, and joiningthe wavelength converter to the light emitting element. The lightemitting element has an element upper surface, an element lower, and anelement side surface. The element lower surface is opposite to theelement upper surface in a thickness direction of the light emittingelement. The element side surface is between the element upper surfaceand the element lower surface. The wavelength converter has a converterlower surface. The joining the wavelength converter to the lightemitting element using an adhesive so that the converter lower surfacefaces the element upper surface. The converter lower surface has anexposed region that does not face the element upper surface viewed alongthe thickness direction. The adhesive covers the element side surfaceand the exposed region.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1A is a view schematically showing a configuration of a lightemitting device according to a first embodiment of the present inventionand a plan view of the light emitting device;

FIG. 1B is a sectional view schematically showing the configuration ofthe light emitting device according to the first embodiment, taken alongX-X of FIG. 1A;

FIG. 1C is a sectional view schematically showing the configuration ofthe light emitting device according to the first embodiment on apartially enlarged scale of FIG. 1B;

FIG. 2A is a sectional view schematically showing a method ofmanufacturing the light emitting device according to the firstembodiment, with a wavelength conversion member preparation step;

FIG. 2B is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a groove part forming step;

FIG. 2C is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with the wavelength conversion member divided through thegroove part forming step;

FIG. 2D is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a division step;

FIG. 2E is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a light transmissive member divided through thedivision step;

FIG. 3A is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a light emitting element mounting step;

FIG. 3B is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a wavelength conversion member joining step;

FIG. 3C is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the firstembodiment, with a light reflective member forming step;

FIG. 4A is a sectional view schematically showing a configuration of alight emitting device according to a second embodiment;

FIG. 4B is a sectional view schematically showing the configuration ofthe light emitting device according to the second embodiment on apartially enlarged scale of FIG. 4A;

FIG. 5A is a sectional view schematically showing a method ofmanufacturing the light emitting device according to the secondembodiment, with a wavelength conversion member preparation step;

FIG. 5B is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the secondembodiment, with a groove part forming step;

FIG. 5C is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the secondembodiment, with a wavelength conversion member divided through thegroove part forming step;

FIG. 5D is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the secondembodiment, with a division step;

FIG. 5E is a sectional view schematically showing the method ofmanufacturing the light emitting device according to the secondembodiment, with a light transmissive member divided through thedivision step;

FIG. 6A is a sectional view schematically showing a configuration of alight emitting device according to a third embodiment; and

FIG. 6B is a sectional view schematically showing the configuration ofthe light emitting device according to the third embodiment on apartially enlarged scale of FIG. 6A.

DESCRIPTION OF THE EMBODIMENTS

The embodiments will now be described with reference to the accompanyingdrawings, wherein like reference numerals designate corresponding oridentical elements throughout the various drawings.

Hereinafter, a light emitting device and a method of manufacturing alight emitting device as one example of the embodiments of the presentinvention will be described with reference to the accompanying drawings.The drawings for reference in the following description schematicallyshow the embodiments of the present invention, and thus scales,intervals, positional relationship, or the like, of members may beexaggerated or the members may be partially omitted from illustration.Moreover, in the following description, the same names and numeralsbasically show the same or similar members, and will be omitted from thedetailed description when appropriate.

First Embodiment Configuration of Light Emitting Device

The configuration of a light emitting device 1 according to the firstembodiment will be described with reference to FIGS. 1A to 1C. The lightemitting device 1 can be used as, for example, a light source of ageneral lighting or an on-vehicle light emitting device. As shown inFIGS. 1A and 1B, the light emitting device 1 includes a substrate 10, alight emitting element 20, conductive members 30, a wavelength converter(hereinafter referred to as a wavelength conversion member) 40, a lightguider (hereinafter referred to as a side light guide member) 51, alight transmitting layer (hereinafter referred to as a lighttransmissive member) 60, a semiconductor element 70, and a reflector(hereinafter referred to as a light reflective member) 80.

The substrate 10 is provided for installation of various members formingthe light emitting device 1 thereon. Here, although omitted fromillustration in FIG. 1B, a wiring portion (conductive pattern) forelectrically connecting an external power source and the light emittingelement 20 is formed on a surface of the substrate 10 with positive andnegative electrodes dielectrically insulated from each other. Mounted onthis wiring portion are the light emitting element 20 and thesemiconductor element 70 described later, with the conductive members 30in between.

As a material of the substrate 10, it is preferable to use an insulatingmaterial through which light from the light emitting element 20 andexternal light are hardly transmitted, and examples of the insulatingmaterial to be used include ceramics such as alumina, aluminum nitride,and LTCC, and a resin material such as a phenol resin, an epoxy resin, apolyimide resin, a BT resin, and polyphthalamide. Moreover, a compositematerial of an insulating material and a metallic member can be used. Ina case where a resin is used as the material of the substrate 10, aninorganic filler such as glass fibers, silicon oxide, titanium oxide, oralumina may be mixed with the resin when needed. This can achieve animprovement in mechanical strength, decrease in coefficient of thermalexpansion, and an improvement in optical reflectance. Note that thethickness of the substrate 10 is not particularly specified and thesubstrate 10 can be formed into any thickness in accordance with apurpose and application.

For the light emitting element 20, it is preferable to use a lightemitting diode having semiconductor layers composed of an n-typesemiconductor layer, a p-type semiconductor layer, and an emissionlayer, and the one of any wavelength can be selected depending on apurpose and application. For example, for a blue light emitting element20 (emitting light of a wavelength of 430 nm to 490 nm) and a greenlight emitting element 20 (emitting light of a wavelength of 490 nm to570 nm), ZnSe, a nitride-based semiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N,0≦X, 0≦Y, X+Y≦1), or GaP can be used. Moreover, for a red light emittingelement 20 (emitting light of a wavelength of 620 nm to 750 nm), forexample, GaAlAs or AlInGaP can be used. In a case where a light emittingdevice 1 using a phosphor is provided, it is preferable to use a nitridesemiconductor (In_(X)Al_(Y)Ga_(1-X-Y)N, 0≦X, 0≦Y, X+Y≦1) capable ofemitting light of a short wavelength which efficiently exciting thephosphor. Moreover, component composition, a color of emitted light, asize, or the like, of the light emitting element 20 can be appropriatelyselected depending on a purpose and application.

The conductive member 30 is provided for the purpose of conducting thelight emitting element 20 and the wiring portion (not shown) on thesubstrate 10. As the conductive member 30, for example, a bump composedof Au or its alloy, eutectic solder such as Au—Sn, Pb—Sn, or lead-freesolder can be used. FIG. 1B shows an example using a bump for theconductive member 30, but the conductive member 30 is not limited to thebump, and may be, for example, a conductive paste.

The wavelength conversion member 40 absorbs at least part of light fromthe light emitting element 20 and converts its wavelength into adifferent wavelength. As shown in FIG. 1B, the wavelength conversionmember 40 has a surface which is larger than an upper surface of thelight emitting element 20 and which is joined to the upper surface ofthe light emitting element 20 with an adhesive (hereinafter referred toas a bonding member) 50 described later in between. As shown in FIG. 1A,the wavelength conversion member 40 covers the upper surface of thelight emitting element 20 in a plan view and also has a lower surfacewhose area is larger than that of the upper surface of the lightemitting element 20. That is, as shown in FIG. 1C, the wavelengthconversion member 40 is formed into a size which projects outwardly froma region immediately above the light emitting element 20. Here, “theupper surface of the light emitting element 20” means a surface of thelight emitting element 20 on a side to which the wavelength conversionmember 40 is joined. Moreover, “the upper surface of the wavelengthconversion member 40” means a surface of the wavelength conversionmember 40 on a side to which the light transmissive member 60 isdisposed, and “the lower surface of the wavelength conversion member 40”described above means a surface of the wavelength conversion member 40on a side on which the light emitting element 20 is mounted.

The upper surface of the wavelength conversion member 40 is formed tohave a smaller area than a lower surface of the light transmissivemember 60 described later in a plan view, as shown in FIGS. 1A and 1B.For example, in a case where the light emitting element 20 has a size of1-mm square, the upper surface of the wavelength conversion member 40has a side which is smaller than that of the lower surface of the lighttransmissive member 60 by 15 μm to 50 μm in length. Here, “the lowersurface of the light transmissive member 60” means a surface of thelight transmissive member 60 on a side on which the wavelengthconversion member 40 is disposed.

Specifically, a side surface 41 of the wavelength conversion member 40is located on an inner side than a side surface of the lighttransmissive member 60 by 15 μm to 50 μm. Then, in a region on a loweredge surface of the light transmissive member 60 where the wavelengthconversion member 40 is not formed, the light reflective member 80described later is provided. As shown in FIG. 1C, the side surface 41 ofthe wavelength conversion member 40 is formed approximatelyperpendicularly to the lower surface of the light transmissive member60. Then, the side light guide member 51 described later is formedcontinuously from a lower corner part of the side surface 41 of thewavelength conversion member 40 to a lower corner part of a side surfaceof the light emitting element 20.

The wavelength conversion member 40 to be used can be formed by mixing alight transmissive material such as a resin, glass, and an inorganicsubstance as a binder of a phosphor, for example Examples of the binderinclude an organic resin binder such as an epoxy resin, a siliconeresin, a phenol resin, and a polyimide resin, and an inorganic bindersuch as glass. An example of the phosphor includes anyttrium-aluminum-garnet-based phosphor (YAG-based phosphor) which is arepresentative phosphor capable of emitting whitish mixed light infavorable combination with a blue light emitting element. In case of thelight emitting device 1 capable of emitting white light, theconcentration of the phosphor contained in the wavelength conversionmember 40 is adjusted so as to permit white light emission. Moreover, itis preferable that the concentration of the phosphor is, for example,approximately 5% to 50%.

Further, it is also possible to achieve emission of light of an ambercolor by using a blue light emitting element for the light emittingelement 20 and using the YAG-based phosphor and a nitride-basedphosphor, rich with red components, for the phosphor. The amber colorcorresponds to a chromaticity range of a region composed of a longwavelength region of an yellow color and a short wavelength region of anyellow-red color in accordance with JIS Z8110 and a region in between anyellow region and the yellow red short wavelength region in accordancewith JIS Z9101 concerning safe color, and corresponds to a region withina range between 580 nm and 600 nm, for example, in terms of a dominantwavelength. Many of phosphors emitting light of the amber color have alow light exchange efficiency, and are desired to increase the phosphorconcentration in order to obtain a desired color tone. Moreover,although there is a concern that the heat generation of the phosphor isgreater than that of another phosphor, the embodiment of the presentinvention makes it possible to increase the phosphor concentration ofthe wavelength conversion member 40 and also reduces its thickness, thuspermitting favorable use of the phosphor emitting light of the ambercolor.

The YAG-based phosphor is a general term of a garnet structurecontaining Y and Al, and is a phosphor activated by at least one kind ofelement selected from rare earth elements, and is excited by blue lightemitted from the light emitting element 20 to emit light. An example ofthe YAG-based phosphor to be used includes(Re_(1-x)Sm_(x))₃(Al_(1-y)Ga_(y))₅O₁₂: Ce (0≦x<1, 0≦y≦1, where Re is atleast one kind of element selected from the group consisting of Y, Gd,and La).

Moreover, a nitride-based phosphor is a phosphor which is activated byat least one kind of rare earth element selected from the groupconsisting of Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu andwhich contains at least one kind of group II element selected from thegroup consisting of Be, Mg, Ca, Sr, Ba, and Zn; at least one kind ofgroup IV element selected from the group consisting of C, Si, Ge, Sn,Ti, Zr, and Hf; and N. The nitride-based phosphor may contain O in thecomposition.

The nitride-based phosphor to be used can be expressed by the generalformula L_(X)M_(Y)N_(((2/3)X+(4/3)Y)): R orL_(X)M_(Y)O_(Z)N_(((2/3)X+(4/3)Y− (2/3)Z)): R (where L is at least onekind of group II element selected from the group consisting of Be, Mg,Ca, Sr, Ba, and Zn; M is at least one kind of group IV element selectedfrom the group consisting of C, Si, Ge, Sn, Ti, Zr, and Hf; R is atleast one kind of rare earth element selected from the group consistingof Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, and Lu; and X, Y, andZ respectively satisfy 0.5≦X≦3, 1.5≦Y≦8, 0<Z≦3).

As the phosphor, other than the YAG-based phosphor and the nitride-basedphosphor, any of those known in the fields, such as a nitride oxidephosphor, KSF (K₂SiF₆:Mn)-based phosphor, or sulfide-based phosphor, canbe appropriately used. These phosphors can be used in a combination or ablending ratio suitable for a desired color tone, to adjust colorrendering properties and color reproducibility.

The wavelength conversion member 40 may use a light-emitting substancereferred to as so-called nanocrystals, quantum dot. Examples of such amaterial can include a semiconductor material such as group II-VI, groupIII-V, or group IV-VI semiconductor, more specifically,highly-scattering nano-size particles such as CdSe, a core-shell typeCdS_(X)Se_(1-X)/ZnS, GaP, and InAs. The particle diameter of such aphosphor can be, for example, 1 nm to 100 nm, and preferablyapproximately 1 nm to 20 nm (approximately 10 to 50 atoms). Use of thewavelength conversion member 40 can suppress inside scattering andscattering of light subjected to color conversion, and further improvelight transmittance.

The wavelength conversion member 40 may be formed of a single layer withone kind of member, a single layer with two or more kinds of members incombination, or two or more single layers stacked on each other. To thewavelength conversion member 40, a light diffusing member may be addedwhen needed. A thickness of the wavelength conversion member 40 can be,for example, 20 μm to 100 μm, and preferably 20 μm to 50 μm. If thethickness of the wavelength conversion member 40 is greater than 100 μm,the heat dissipation property tends to deteriorate. Moreover, in termsof heat dissipation property, a smaller thickness of the wavelengthconversion member 40 is more preferable, but too small thickness of thewavelength conversion member 40 reduces an amount of phosphors,resulting in tendency to reduce a chromaticity range of emitted light.In view of this, the wavelength conversion member 40 has the appropriatethickness should be formed to have the appropriate thickness describedabove.

The side light guide member 51 guides light from the light emittingelement 20 towards the wavelength conversion member 40. As shown in FIG.1C, the side light guide member 51 is formed from the side surface ofthe light emitting element 20 to the lower edge surface (an exposedregion that does not face the upper surface of the light emittingelement 20 in plain view) of the wavelength conversion member 40.Specifically, this side light guide member 51 is formed by extending thebonding member 50 joining the light emitting element 20 and thewavelength conversion member 40, from the side surface of the lightemitting element 20 to the lower edge surface of the wavelengthconversion member 40. That is, the side light guide member 51 is formedof the same material as that of the bonding member 50. Providing such aside light guide member 51 permits reflection of light exiting from theside surface of the light emitting element 20 and incidence of the lightinto the wavelength conversion member 40, improving the light conversionefficiency of the wavelength conversion member 40.

As the bonding member 50 forming the side light guide member 51, it ispreferable to use a light transmissive material capable of effectivelyguiding the light exiting from the light emitting element 20 to thewavelength conversion member 40 and optically coupling together thelight emitting element 20 and the wavelength conversion member 40. Asthe bonding member 50, for example, an organic resin such as an epoxyresin, a silicone resin, a phenol resin, and a polyimide resin can beused, and it is preferable to use a silicone resin. A smaller thicknessof the bonding member 50 formed between the light emitting element 20and the wavelength conversion member 40 is preferable, whereby the heatdissipation property improves and loss of light transmitted through thebonding member 50 between the light emitting element 20 and thewavelength conversion member 40 decreases. Thus, optical output of thelight emitting device 1 improves.

In a sectional view vertically cut as shown in FIG. 1C, the side lightguide member 51 is formed into a sectionally triangle shape in which thebonding member 50 extends on the side surface of the light emittingelement 20 and at a corner part of the lower edge surface of thewavelength conversion member 40 and the thickness of the bonding member50 decreases towards the lower surface of the light emitting element 20.As shown in FIG. 1B, a light reflective member 80 described below isdisposed so as to make contact with the side light guide member 51having this sectionally triangle shape. As a result, the light exitingfrom the side surface of the light emitting element 20 is reflected onan interface between the side light guide member 51 having thissectionally triangle shape and the light reflective member 80, and ismade incident on the edge of the wavelength conversion member 40projecting outwardly from the upper surface of the light emittingelement 20, further improving luminance of the emitted light of thelight emitting device 1.

Here, the side light guide member 51 can be formed by, for example, uponjoining the wavelength conversion member 40 formed on a lower surface ofthe light transmissive member 60 with the light emitting element 20,dropping the bonding member 50 on the upper surface of this lightemitting element 20 and extending, up to the side surface of the lightemitting element 20, an excessive amount of the bonding member 50 whichis the rest of the bonding member 50 required for the bonding with theupper surface of the light emitting element 20. The sectionally triangleshape of the side light guide member 51 can be formed by optimizingwettability and viscosity of the silicone resin to the side surface ofthe light emitting element 20 and the lower surface of the wavelengthconversion member 40.

Further, in a case where the silicone resin is used as a binder of thewavelength conversion member 40, it is also preferable to use a siliconeresin for the bonding member 50. This consequently can reduce adifference in refractive index between the wavelength conversion member40 and the bonding member 50, thus making it possible to increase lightincident on the wavelength conversion member 40 from the bonding member50.

The light transmissive member 60 is a member provided separately fromthe wavelength conversion member 40 containing a phosphor, and isprovided for the purpose of supporting the wavelength conversion member40 formed on its lower surface. In a cross section of the light emittingdevice 1 as shown in FIG. 1B, the light transmissive member 60 isdisposed on the upper surface of the wavelength conversion member 40.Moreover, as shown in FIG. 1A, the light transmissive member 60 coversthe upper surface of the light emitting element 20 and the upper surfaceof the wavelength conversion member 40, and the lower surface of thelight transmissive member 60 has a larger area than both the uppersurface of the light emitting element 20 and the upper surface of thewavelength conversion member 40. That is, as shown in FIG. 1C, the lighttransmissive member 60 is formed into such a size that the lighttransmissive member 60 projects outwardly from a region immediatelyabove the light emitting element 20 and a region immediately above thewavelength conversion member 40.

As the light transmissive member 60, a plate-like body formed of a lighttransmissive material such as glass or a resin can be used. As theglass, for example, borosilicate glass or quartz glass can be used, andas the resin, for example, a silicone resin or an epoxy resin can beused. Note that the light transmissive member 60 may include a lightdiffusing member. Increasing the phosphor concentration of thewavelength conversion member 40 described above tends to cause colorunevenness, but the light diffusing member included in the lighttransmissive member 60 can suppress the color unevenness and luminanceunevenness. As the light diffusing member, for example, titanium oxide,barium titanate, aluminum oxide, or silicon oxide can be used.

The light transmissive member 60 may have any thickness which canprovide the wavelength conversion member 40 with sufficient mechanicalstrength without reducing mechanical strength during the production.Since too large thickness of the light transmissive member 60 leads to atrouble for downsizing of the light emitting device 1 or lower the heatdissipation property, it is preferable to provide an appropriatethickness in view of this. Moreover, the upper surface of the lighttransmissive member 60, serving as a light emitting surface, is notlimited to a flat surface, and may have small irregularities. Forming ofthe small irregularities on such a light emitting surface makes itpossible to promote scattering of light exiting from this light emittingsurface and further suppress the luminance unevenness and the colorunevenness.

The light emitting device 1 includes a semiconductor element 70 disposedon the substrate 10 separately from the light emitting element 20 butadjacently to this light emitting element 20. As the semiconductorelement 70, another light emitting element not intended for lightemission of the light emitting device 1, a transistor for controllingthe light emitting element or a protective element can be used.

The protective element described above is an element for protecting thelight emitting element 20 from element breakage or performancedegradation caused by excessive voltage application, and is specificallyformed of a Zener diode that turns into an electrified state as a resultof application of a voltage equal to or greater than a specifiedvoltage. The protective element is electrically connected by theconductive member 30 inversely in parallel to a p-electrode and ann-electrode of the light emitting element 20. This can consequentlyprevents a voltage across the p- and n-electrodes of the light emittingelement 20 from becoming equal to or greater than the Zener voltage, andcan appropriately prevent occurrence of the element breakage and theperformance degradation of the light emitting element 20 caused by theapplication of excessive voltage.

The light reflective member 80 is provided for reflecting the lightemitted from the light emitting element 20. As shown in FIG. 1B, thelight reflective member 80 is disposed so as to cover all the membersdisposed on the substrate 10, and is disposed at least on the sidesurfaces of the wavelength conversion member 40, the light transmissivemember 60, and the side light guide member 51. As a result, the lightreflective member 80 permits the light exiting from the light emittingelement 20 to be incident on the wavelength conversion member 40. Morespecifically, the light reflective member 80 is disposed not only on theside surfaces of the wavelength conversion member 40, the lighttransmissive member 60, and the side light guide member 51, but also onthe lower surface of the light-emitting element 20 and a lower surface,side surfaces, and an upper surface of the semiconductor element 70.

As the light reflective member 80, an insulating material is preferablyused, or for the purpose of ensuring some degree of strength, forexample, a thermosetting resin or a thermoplastic resin can be used. Thelight reflective member 80 can be formed by using a resin such as asilicone resin, a modified silicone resin, an epoxy resin, a modifiedepoxy resin, an acrylic resin, a phenol resin, a BT resin, and PPA or ahybrid resin containing at least one kind of these resins, and a lightreflective member. Of these substance described above, as a basepolymer, it is preferable to use a resin that contains a silicone resinwith an excellent heat resistance, an excellent electrical insulatingproperty, and flexibility. Examples of the light reflective member 80include titanium oxide, silicon oxide, zirconium oxide, magnesium oxide,calcium carbonate, calcium hydroxide, calcium silicate, zinc oxide,barium titanate, potassium titanate, alumina, aluminum nitride, boronnitride, and mullite. Of these substances, titanium oxide is preferablesince it is stable for moisture, or the like, and has high refractiveindex.

With the light emitting device 1 having the configuration describedabove, light exiting from the side of the light emitting element 20 canbe extracted to the front by use of the side light guide member 51, andproviding a smaller area for the upper surface of the wavelengthconversion member 40 than for the lower surface of the lighttransmissive member 60 to reduce a surface on which the wavelengthconversion member 40 makes contact with the light transmissive member 60can reduce an yellow light component of the end part of the lightemitting surface. Therefore, with the light emitting device 1, frontluminance can be improved and, at the same time, occurrence of colorunevenness at an outer circumferential part of the light emittingsurface can be reduced.

Method of Manufacturing Light Emitting Device

Hereinafter, the method of manufacturing the light emitting device 1according to the first embodiment of the present invention will bedescribed with reference to FIGS. 2A to 2E and FIGS. 3A to 3C. In themethod of manufacturing the light emitting device 1, a wavelengthconversion member preparation step (FIG. 2A), a groove part forming step(FIGS. 2B and 2C), a division step (FIGS. 2D and 2E), a light emittingelement mounting step (FIG. 3A), a wavelength conversion member joiningstep (FIG. 3B), and a light reflective member arrangement step (FIG. 3C)are performed in order.

The wavelength conversion member preparation step is a step of preparingthe light transmissive member 60 having the wavelength conversion member40 formed on its lower surface. In the wavelength conversion memberpreparation step, the light transmissive member 60 sufficiently largerthan a plurality of light emitting elements 20 is prepared, and as shownin FIG. 2A, this light transmissive member 60 is used as a support andthe wavelength conversion member 40 is formed on the lower surface ofthe light transmissive member 60. As a method of forming the wavelengthconversion member 40, printing, compression molding, a phosphorelectrodeposition method, a phosphor sheet method, or the like, can beused. In the description below, the lower surface of the lighttransmissive member 60 means a surface on a side of the lighttransmissive member 60 on which the wavelength conversion member 40 isdisposed, as is the case with FIG. 1B.

Here, in a case where the printing is used, paste containing a phosphor,a binder, and a solvent is prepared, and this paste is applied to thelower surface of the light transmissive member 60, and dried to therebyform the wavelength conversion member 40. As the binder described above,an organic resin binder such as an epoxy resin, a silicone resin, aphenol resin, or a polyimide resin or an inorganic binder such as glasscan be used. In a case where the compression molding is used, a materialof the wavelength conversion member 40 containing a phosphor in a binderis molded with a die to thereby form the wavelength conversion member 40on the lower surface of the light transmissive member 60. In a casewhere the phosphor electrodeposition method is used, anelectrically-conductive, thin film capable of having light transmissiveproperty is formed and the charged phosphor is cumulated on the thinfilm by use of electrophoresis to thereby form the wavelength conversionmember 40 on the lower surface of the light transmissive member 60. In acase where the phosphor sheet method is used, a phosphor is kneaded witha silicone resin to form a phosphor sheet machined into a sheet-likeshape. The wavelength conversion member 40 is formed from the phosphorsheet.

The groove part forming step is a step of forming a groove part at thewavelength conversion member 40 provided on the light transmissivemember 60. Here, the groove part is provided for zoning the lighttransmissive member 60 for the individual light emitting element 20. Inthe groove part forming step, as shown in FIG. 2B, a blade B1 having apredetermined width (thick blade) is used to substantiallyperpendicularly divide the wavelength conversion member 40 to form agroove part D as shown in FIG. 2C. Here, in the groove part formingstep, it is preferable to use the blade B1 whose width is larger thanthat of a blade B2 in the division step described later by approximately30 μm to 100 μm. As a result, as described later, the upper surface ofthe wavelength conversion member 40 can be formed to have a smaller areathan the lower surface of the light transmissive member 60 in a planview (see FIG. 2E). In the groove part forming step, the groove part Dis formed in such a manner that the upper surface of the wavelengthconversion member 40 covers the upper surface of the light emittingelement 20 described later (see FIG. 3A) and has a greater area thanthat of the upper surface of the light emitting element 20 to therebydivide wavelength conversion member 40. In the groove part forming step,as shown in FIG. 2B, the groove part D is formed on the wavelengthconversion member 40 while the lower surface of the light transmissivemember 60 faces upward.

In FIG. 2B, as one example of the groove part forming step, the blade B1is used, but in the groove part forming step, instead of the blade B1,laser light may be used to divide the wavelength conversion member 40,or etching may be adopted to divide the wavelength conversion member 40.

The division step is a step of dividing the light transmissive member 60at the groove part D. In the division step, as shown in FIG. 2D, theblade (thin blade) B2 having a predetermined width is used to divide thelight transmissive member 60 so as to pass through a center of thegroove part D formed in the groove part forming step. Here, in thedivision step, it is preferable to use the blade B2 whose width issmaller than that of the blade B1 in the groove part forming stepdescribed above by approximately 30 μm to 100 μm. As a result, as shownin FIG. 2E, the upper surface of the wavelength conversion member 40 canbe formed with one side which is smaller in length than the lowersurface of the light transmissive member 60 by 15 μm to 50 μm in a planview. Moreover, in the division step, the light transmissive member 60is divided in such a manner that the light transmissive member 60 coversthe upper surface of the light emitting element 20 in a plan view andthe lower surface of the light transmissive member 60 has a larger areathan the upper surface of the light emitting element 20. As a result, asshown in FIG. 2E, a level difference can be formed between thewavelength conversion member 40 and the light transmissive member 60.

In FIG. 2D, as one example of the division step, the division by use ofthe blade B2 has been illustrated, but instead of the blade B2, laserlight may be used to divide the light transmissive member 60 in thedivision step.

Moreover, as described above, by forming the groove part D at thewavelength conversion member 40 with the thick blade B1 and thendividing the light transmissive member 60 with the thin blade B2,attachment of the wavelength conversion member 40 to the blade B2 at thetime of dividing the light transmissive member 60 can be prevented.Performing the forming of the groove part D at the wavelength conversionmember 40 and the division of the light transmissive member 60 withblades having the same width is likely to cause attachment of thewavelength conversion member 40 to the blade at the time of dividing thelight transmissive member 60, resulting in risks that the wavelengthconversion member 40 is attached to a division surface at the time ofdivision or degradation of blade rotation occurs and thus workefficiency deteriorates. From these viewpoints, it is preferable thatthe upper surface of the wavelength conversion member 40 has a smallerarea than the lower surface of the light transmissive member 60.

The light emitting element mounting step is a step of mounting the lightemitting element 20 on the substrate 10. In the light emitting elementmounting step, as shown in FIG. 3A, a plurality of light emittingelements 20 are mounted on the wiring portion (not shown) on thesubstrate 10 with the conductive members 30 in between. Similarly, onthe substrate 10 between the light emitting element 20 and the lightemitting element 20 adjacent thereto, the semiconductor element 70 ismounted. As a method of mounting the light emitting element 20 and thesemiconductor element 70, flip-chip mounting can be used. Note that, themounting of the semiconductor element 70 is not necessary and can beomitted.

The wavelength conversion member joining step is a step of joining thewavelength conversion member 40 formed on the lower surface of the lighttransmissive member 60 as shown in FIG. 2E to the upper surface of thelight emitting element 20 shown in FIG. 3A with the bonding member 50 inbetween. In the wavelength conversion member joining step, as shown inFIG. 3B, the wavelength conversion member 40 formed on the lower surfaceof the light transmissive member 60 in advance, with its side beingoriented to face the upper surface of the light emitting element 20, isjoined to the upper surface of the light emitting element 20 with thebonding member 50 in between.

Here, in the wavelength conversion member joining step, by pressing thelight transmissive member 60, the bonding member 50 provided between thelight emitting element 20 and the wavelength conversion member 40extends from the side surface of the light emitting element 20 to thelower edge surface of the wavelength conversion member 40 and form theside light guide member 51. Specifically, in the wavelength conversionmember joining step, when joining of the wavelength conversion member 40to the light emitting element 20, a larger amount of the bonding member50 is applied to the upper surface of the light emitting element 20 andan excessive amount of the bonding member 50 which is the rest of thebonding member 50 required for the bonding with the upper surface of thelight emitting element 20 is extended on the side surface of the lightemitting element 20, thereby forming the side light guide member 51having a sectionally triangle shape as shown in FIG. 3B.

The bonding member 50 extends on the side surface of the light emittingelement 20 to form the side light guide member 51, but reach of thebonding member 50 extending on the side surface of the light emittingelement 20 at an upper surface of the substrate 10 brings about a riskthat the light exiting from the light emitting element 20 is madeincident on the upper surface of the substrate 10 through the bondingmember 50 and is thus absorbed by the substrate 10. Thus, viscosity andan amount of the bonding member 50 need to be appropriately adjusted tosuch degrees that avoid the reach of the bonding member 50 at the uppersurface of the substrate 10. More specifically, for example, consideringexposure of a lower corner part of the side surface of the lightemitting element 20 from the side light guide member 51 as a standard,the amount and viscosity of the bonding member 50 can be adjusted.

In the wavelength conversion member joining step, the light transmissivemember 60 having a substantially rectangular shape in a plan view isdisposed on the upper surface of the light emitting element 20 having asubstantially rectangular shape in a plan view in such a manner thatdirections of their corner parts overlap with each other. The bondingmember 50 dropped on the upper surface of the light emitting element 20having a substantially rectangular shape in a plan view is pressed bythe light transmissive member 60 to thereby widen horizontally through360 degrees. Here, since the light emitting element 20 has asubstantially rectangular shape in a plan view, the widened bondingmember 50 spreads easily and quickly to each of center parts of the fourside surfaces of the light emitting element 20, and finally reaches atthe corner parts of the side surfaces of the light emitting element 20.There is a risk that the bonding member 50 extending all the sidesurfaces is pressed, then reaches at the lower surface of the lightemitting element 20 or the substrate 10. That is, exposure of the lowercorner parts of the light emitting element 20 from the bonding member 50can be set as a standard that the bonding member 50 has not yet reachedat the lower surface of the light emitting element 20 or the substrate10, facilitating the management of manufacturing steps. It can beassumed that light release is small at a part (corner part) includingintersections of the sides forming an outline of the light emittingelement 20 having a substantially rectangular shape in a plan view, andthus light loss caused by exposing the lower corner part from the sidelight guide member 51 is minimized.

Moreover, the wavelength conversion member joining step can also beperformed by adjusting an amount of the binder of the wavelengthconversion member 40 while this binder is semicured. The semicuredwavelength conversion member 40 can be pressed against the upper surfaceof the light emitting element 20 to thereby permit extension of part ofthe binder on the side surface of the light emitting element 20.

The light reflective member arrangement step is, as shown in FIG. 3C, astep of arranging the light reflective member on the substrate 10 and,for example, around the light emitting element 20. In the lightreflective member arrangement step, for example, a resin dischargedevice which can move, for example, in a vertical direction or ahorizontal direction with respect to the substrate 10 is used to fill anupper side of the fixed substrate 10 with a resin forming the lightreflective member 80.

With the method of manufacturing the light emitting device 1 forperforming the steps as described above, the light guide member 51 isformed by extending the bonding member 50 from the side surface of thelight emitting element 20 to the lower edge side of the wavelengthconversion member 40 forms the side light, which extract the lightemitted from the side of the light emitting element 20 to the front, andalso makes an area of the upper surface of the wavelength conversionmember 40 smaller than that of the lower surface of the lighttransmissive member 60 to reduce a surface on which the wavelengthconversion member 40 makes contact with the light transmissive member60. Therefore, the method of manufacturing the light emitting device 1permits manufacturing of a light emitting device 1 capable of improvingthe front luminance and reducing the occurrence of ring-shaped colorunevenness at an outer circumferential part of the light emittingsurface.

Second Embodiment Configuration of Light Emitting Device

The configuration of the light emitting device 1A according to thesecond embodiment will be described with reference to FIGS. 4A and 4B.As shown in FIG. 4A, the light emitting device 1A has the sameconfiguration as the light emitting device 1 (see FIG. 1B) describedabove, except for a configuration of a wavelength conversion member 40A.

As shown in FIG. 4B, the wavelength conversion member 40A of the lightemitting device 1A has an upper surface whose area is equal to that of alower surface of the light transmissive member 60. Moreover, thewavelength conversion member 40A has an end part, that is, a regionlocated on an outer side of the light emitting element 20 in a planview, more thinly formed than other regions. The wavelength conversionmember 40A is formed in such a manner that its region located on theouter side of the light emitting element 20 becomes gradually thinnertowards outer circumference.

More specifically, the wavelength conversion member 40A is formed in aconstant thickness in a region (referred to as a first wavelengthconverter part) immediately above the light emitting element 20, and aside surface 41A of the wavelength conversion member 40A is inclinedtowards the outer circumference at the end part of the wavelengthconversion member 40A, that is, in the region (referred to as a secondwavelength converter part) located on the outer side of the lightemitting element 20. In other words, in a region between the sidesurface of the light emitting element 20 and the side surface of thelight transmissive member 60, the wavelength conversion member 40A isformed into a tapered shape so as to become thinner towards the outercircumference at a constant angle. A region in which the wavelengthconversion member 40A is formed into a tapered shape, that is, theregion between the side surface of the light emitting element 20 and theside surface of the light transmissive member 60 specifically has awidth of 15 μm to 50 μm, if the light-emitting element 20 describedabove has a size of a 1-mm square, for example.

In the light emitting device 1A having the configuration describedabove, unlike the light emitting device 1 in which the wavelengthconversion member 40A on a lower edge side of the light transmissivemember 60 is not completely removed, the end part of the wavelengthconversion member 40A is formed to be tapered towards the outercircumference, thereby permitting more precise adjustment of an yellowcomponent of the end part of the light emitting surface, which cantherefore more effectively reduce the color unevenness on the lightemitting surface.

Method of Manufacturing Light Emitting Device

Hereinafter, the method of manufacturing the light emitting device 1Aaccording to the second embodiment of the present invention will bedescribed with reference to FIGS. 5A to 5E. In the method ofmanufacturing the light emitting device 1A, a wavelength conversionmember preparation step (FIG. 5A), a groove part forming step (FIGS. 5Band 5C), a division step (FIGS. 5D and 5E), a light emitting elementmounting step (FIG. 3A), a wavelength conversion member joining step(FIG. 3B), and a light reflective member arrangement step (FIG. 3C) areperformed in order. Note that the light emitting element mounting stepand the following steps are the same as those of the method ofmanufacturing the light emitting device 1 according to the firstembodiment, and thus are omitted from the description.

In the wavelength conversion member preparation step, a lighttransmissive member 60 having a size sufficiently larger than that of aplurality of light emitting elements 20 is prepared, and as shown inFIG. 5A, printing, compression molding, a phosphor electrodepositionmethod, or a phosphor sheet method is used to form a wavelengthconversion member 40A on the lower surface of the light transmissivemember 60.

In the groove part forming step, as shown in FIG. 5B, laser light L1having a predetermined width is used to dice and divide the wavelengthconversion member 40A, then form a groove part D as shown in FIG. 5C.Here, in the groove part forming step, adjusting a condition of thelaser light L1, the groove part D is formed in such a manner that aregion of the wavelength conversion member 40A located on an outer sideof the light emitting element 20 is thinner than a region immediatelyabove the light emitting element 20 in a plan view, more specifically,the wavelength conversion member 40A becomes gradually thinner towardsthe groove part D. As a result, the side surface 41A of the wavelengthconversion member 40A is machined in a tapered shape. Moreover, in thegroove part forming step, the groove part D is formed in such a mannerthat the wavelength conversion member 40A covers the upper surface ofthe light emitting element 20 and the lower surface of the wavelengthconversion member 40A has a larger area than the upper surface of thelight emitting element 20, thereby dividing the wavelength conversionmember 40.

In FIG. 5B, as one example of the groove part forming step, the laserlight L1 is used, but instead of the laser light L1, the wavelengthconversion member 40A may be divided by a blade in the groove partforming step, or the wavelength conversion member 40A may be divided byetching.

In the division step, as shown in FIGS. 5D and 5E, a blade B3 having apredetermined width is used to dice and perpendicularly divide the lighttransmissive member 60 so as to pass through a center of the groove partD formed in the groove part forming step. Moreover, in the divisionstep, the light transmissive member 60 is divided in such a manner thatthe light transmissive member 60 covers the upper surface of the lightemitting element 20 in a plan view and the lower surface of the lighttransmissive member 60 has a larger area than the upper surface of thelight emitting element 20. Then, the light emitting device 1A as shownin FIG. 4A is manufactured through the light emitting element mountingstep (FIG. 3A), the wavelength conversion member joining step (FIG. 3B),and the light reflective member arrangement step (FIG. 3C).

In FIG. 5D, as one example of the division step, the blade B3 is used,but instead of the blade B3, laser light may be used to divide the lighttransmissive member 60 in the division step.

Third Embodiment

A configuration of a light emitting device 1B according to the thirdembodiment will be described with reference to FIGS. 6A and 6B. As shownin FIG. 6A, the light emitting device 1B has the same configuration asthe light emitting device 1 except for a configuration of a wavelengthconversion member 40B (see FIG. 1B).

As shown in FIG. 6B, the wavelength conversion member 40B of the lightemitting device 1B has an upper surface formed to have the same size ofarea as that of the lower surface of the light transmissive member 60.Moreover, the wavelength conversion member 40B has an end part, that is,a region located on an outer side of the light emitting element 20 in aplanar view, which is formed more thinly than other regions. Thewavelength conversion member 40B is formed in such a manner that theregion located on the outer side of the light emitting element 20becomes thinner towards outer circumference while being curved.

More specifically, the wavelength conversion member 40B has a constantthickness in the region immediately above the light emitting element 20,and a side surface 41B of the wavelength conversion member 40B is formedin such a manner to be curved and inclined towards outer circumferencein the region located on the outer side of the light emitting element20, that is, the region between the side surface of the light emittingelement 20 and the side surface of the light transmissive member 60. Theregion in which the wavelength conversion member 40B is formed into acurve, that is, the region between the side surface of the lightemitting element 20 and the side surface of the light transmissivemember 60 specifically has a width of 15 μm to 50 μm, if the lightemitting element 20 has a size of a 1-mm square, for example.

Here, to manufacture the light emitting device 1B provided with thewavelength conversion member 40B as described above, in a groove partforming step, a condition of the laser light L1 may be adjusted, agroove part D may be formed in such a manner that the region of thewavelength conversion member 40B located on the outer side of the lightemitting element 20 in a plan view becomes thinner towards the groovepart D while being curved, and the side surface 41B of the wavelengthconversion member 40B may be machined into a curve. The steps formanufacturing the light emitting device 1B are the same as those of thelight emitting device 1A described above except for the groove partforming step.

In the light emitting device 1B having the configuration describedabove, the shape of the end part of the wavelength conversion member 40Bcan be machined into a curve towards outer circumference to therebyenable an yellow component of the end part of a light emitting surfaceto be adjusted more finely, similarly to the light emitting device 1A,thus permitting more effective reduction in color unevenness on thelight emitting surface.

The light emitting device and the method of manufacturing the lightemitting device according to the embodiments have been described indetailed description of embodiments, but the spirits of the presentinvention are not limited to these descriptions, and should be widelyinterpreted from the description in the claims. Moreover, it is needlessto say that various modifications, revisions, or the like, based onthese descriptions are also included in the spirits of the presentinvention.

For example, the light emitting devices 1 to 1B may be provided withunderfilling in a gap between the light emitting element 20 and thesemiconductor element 70, and the conductive member 30 when needed. Theunderfilling is provided for protecting the light emitting element 20,the semiconductor element 70, the conductive member 30, or the like,disposed on the substrate 10 from dust, moisture, external force, or thelike, As a material of the underfilling, for example, a silicone resin,an epoxy resin, or a urea resin can be used. Moreover, in addition tosuch materials, a coloring agent, a light diffusing member, a filler, aphosphor member, or the like, can be contained when necessary.

A light emitting device according to one aspect of the embodiment of thepresent invention includes: a light emitting element; a wavelengthconversion member having a surface which is larger than an upper surfaceof the light emitting element and is joined to the upper surface of thelight emitting element; a light transmissive member having a larger areathan the upper surface of the light emitting element and disposed on anupper surface of the wavelength conversion member; a side light guidemember with light transmissive property formed from a side surface ofthe light emitting element to a lower edge surface of the wavelengthconversion member; and a light reflective member disposed at least eachside surface of the wavelength conversion member, the light transmissivemember, and the side light guide member, wherein the wavelengthconversion member has the upper surface smaller than a lower surface ofthe light transmissive member, or a region located on an outer side ofthe light emitting element is formed more thinly than a regionimmediately above the light emitting element.

A method of manufacturing a light emitting device according to anotheraspect of the embodiment of the present invention includes the steps of:preparing a light transmissive member having a lower surface on which awavelength conversion member is formed; forming a groove part at thewavelength conversion member; dividing the light transmissive memberthrough the groove part; and joining the wavelength conversion memberformed on the lower surface of the light transmissive member to an uppersurface of a light emitting element with a bonding member in between,wherein the step of forming the groove part forms the groove part insuch a manner that an upper surface of the wavelength conversion memberhas a larger area than the upper surface of the light emitting element,and forms the groove part in such a manner that the upper surface of thewavelength conversion member has a smaller area than the lower surfaceof the light transmissive member or that a region located on an outerside of the light emitting element is thinner than a region immediatelyabove the light emitting element, and the step of joining the wavelengthconversion member forms a side light guide member by extending a bondingmember which is provided between the light emitting element and thewavelength conversion member from a side surface of the light emittingelement to a lower edge surface of the wavelength conversion member.

With the light emitting device according to the embodiments of thepresent invention, light emitted from the side surface of the lightemitting element can be extracted to the front by use of the side lightguide member, and also an yellow light component of an end part of alight emitting surface can be reduced by reducing a surface on which thewavelength conversion member makes contact with the light transmissivemember or by machining a shape of the end part of the wavelengthconversion member. Therefore, with the light emitting device, the frontluminance can be improved, and also occurrence of color unevenness at anouter circumferential part of the light emitting surface can be reduced.

With the method of manufacturing a light emitting device according tothe embodiments of the present invention, the bonding member is extendedfrom the side surface of the light emitting element to the lower edgesurface of the wavelength conversion member to thereby form a side lightguide member for extracting light emitted from the side surface of thelight emitting element to the front, to reduce the surface on which thewavelength conversion member makes contact with the light transmissivemember, or to machine a shape of the end part of the wavelengthconversion member. Therefore, the method of manufacturing the lightemitting device permits manufacture of a light emitting device capableof improving the front luminance and also reducing occurrence of colorunevenness at the outer circumferential part of the light emittingsurface.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed is:
 1. A light emitting device comprising: a lightemitting element having an element upper surface, an element lowersurface opposite to the element upper surface in a thickness directionof the light emitting element, and an element side surface between theelement upper surface and the element lower surface; a wavelengthconverter having a converter lower surface and provided to be connectedto the light emitting element such that the converter lower surfacefaces the element upper surface, the converter lower surface having anexposed region that does not face the element upper surface viewed alongthe thickness direction, the wavelength converter comprising: a firstwavelength converter part facing the element upper surface viewed alongthe thickness direction and having a first thickness in the thicknessdirection; and a second wavelength converter part not facing the elementupper surface viewed along the thickness direction and having a secondthickness in the thickness direction, the second thickness being thinnerthan the first thickness; and a light guider to guide light from thelight emitting element to the wavelength converter, the light guidercovering the element side surface and the exposed region.
 2. The lightemitting device according to claim 1, further comprising a lightreflector covering the wavelength converter and the light guider.
 3. Thelight emitting device according to claim 1, wherein the light emittingelement is joined to the wavelength converter via an adhesive, whereinthe adhesive includes the light guider.
 4. The light emitting deviceaccording to claim 1, further comprising a light transmitting layer,wherein the wavelength converter has a converter upper surface oppositeto the converter lower surface in the thickness direction, wherein thelight transmitting layer has a layer lower surface facing the converterupper surface, and wherein the converter upper surface has thesubstantially same area as the layer lower surface, and wherein thesecond thickness becomes thinner as the second wavelength converter partseparates from the light emitting element.
 5. The light emitting deviceaccording to claim 4, wherein the second thickness becomes thinner asthe second wavelength converter part separates from the light emittingelement in a curved shape.
 6. The light emitting device according toclaim 4, wherein the light transmitting layer includes glass.
 7. Thelight emitting device according to claim 4, wherein the lighttransmitting layer includes a light diffuser.